Java HttpServer讀取超時以及來自同一應用程序的后續請求彼此之間過於接近

Question

由於Java HttpServer的問題，我要瘋了。 我使用上下文等創建服務器，然后從客戶端應用程序使用URLConnection和InputStream連接到服務器。

問題在於，當客戶端執行更多彼此之間過於接近的后續請求時，客戶端通常會（沒有明顯的邏輯）讀取超時。 為了避免這種情況，我必須從連接和下一個連接中放入sleep（5000） （為什么要設置5000？因為在5000以下仍會給出超時）。

我已經嘗試過使用Executors（與Executors.newCachedThreadPool（）和Executors.newFixedThreadPool（10）一起使用 ，但什么也沒有。

使用2個客戶端的另一件奇怪的事情：

1. 客戶1：第一個請求=確定
2. 客戶2：第一個請求=確定
3. 等待幾秒鍾
4. 客戶端1：第二個請求=可以
5. 客戶端1：第三個請求=凍結，它不斷嘗試（請參見下面的代碼），然后給出超時
6. 客戶端2：第二個請求=正常（客戶端1仍在嘗試並超時）

所以..問題似乎與特定的客戶端實例有關

這里有一些代碼

服務器

try {
        cryptex = new ServerCryptex();
        final Executor multi = Executors.newCachedThreadPool();
        server = HttpServer.create(new InetSocketAddress(8888), 50);

        addContexts();

        server.setExecutor(multi);
        server.start();


    } catch (IOException ex) {
        Logger.getLogger(MyHttpServer.class.getName()).log(Level.SEVERE, null, ex);
    }

上下文添加了

server.createContext("/empty", new HttpHandler_Empty(this));

等等

客戶

這是執行請求的功能

 public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    URLConnection con = url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(7000);
    InputStream is = null;

    **NO PROBLEM UNTIL HERE**

    for (int i = 0; i < 5; i++) {
        try {
            System.out.println("open the stream, try #" + i);

            **TIMEOUT ON THE NEXT LINE**

            is = con.getInputStream();
            break;
        } catch (java.net.SocketTimeoutException ex) {

            **I THOUGHT TO USE THIS WAY TO TRY 5 TIMES THE CONNECTION BEFORE GIVING ERROR TO THE USER, BUT NOTHING. **

            sleep(500);
            if (i == 4) {
                throw ex;
            }
        }
    }
    String reply = readReply(is);
    System.out.println("read reply:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

真實代碼（無5次嘗試代碼）

public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    HttpURLConnection con = (HttpURLConnection) url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(2000);

    System.out.println("open the stream");
    InputStream is = con.getInputStream();

    String reply = readReply(is);
    System.out.println("risposta letta:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

和錯誤

giu 12, 2018 10:58:01 PM gui.Client_GUI aggiornaUdg
GRAVE: null 
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1569)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
at net.ClientConnector.performRequest(ClientConnector.java:96)
at net.ClientConnector.checkKey(ClientConnector.java:43)
at net.Client.getUDG(Client.java:56)
at gui.Client_GUI.aggiornaUdg(Client_GUI.java:2407)
at gui.Client_GUI.jButton1ActionPerformed(Client_GUI.java:1917)
at gui.Client_GUI.access$000(Client_GUI.java:53)
at gui.Client_GUI$1.actionPerformed(Client_GUI.java:390)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

會是什么呢？ 您有什么建議可以避免這個問題？ 提前非常感謝你

Answer 1

我不知道問題的原因。。但是我使用Apache Java HTTP Client Library解決了

這里的代碼

public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);

    HttpClient client = HttpClientBuilder.create().build();
    HttpGet request = new HttpGet(url.toString());

    // add request header
    HttpResponse response = client.execute(request);

    System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

    String t = "";
    String s = rd.readLine();
    while (s != null) {
        t = t + s;
        s = rd.readLine();
    }

    System.out.println("risposta letta:" + t);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(t);
    } else {
        return t.getBytes();
    }
}